Apparatus for the control of electric motors.



APPLICATION FILED JAN, 26, I915- Patented July 20, 1915.

WITNESSES *riNrrnn s'rnrns PATENT orricn.

JOHN s. Ho 'LInAnoF WILKINSBURG, PENNSYLVANIA, AssIeNon TO THE UNION 1 SWITCH a SIGNAL COMPANY, or SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

APPARATUS FOR THE CONTROL OF ELECTRIC MOTORS.

Specification of Letters Patent. i uly 1915.

Original application filed Apri1 23, 1914, Serial. No. 833,392. Divided and this application filed January 26,

I will describe one form of'apparatus embodying my invention, and then point out -the novel features thereof in claims.

The accompanying drawing is a diagrammatic viewshowing one form of apparatus embodying my invention applied to a form of railway trafli ccontrolling apparatus, as

railway trafiic controlling device,

described in my above mentionedco-pending application. I r x r Referring to the drawing, A designatles a ere shown as being a railway switch, which switch is operated by an electric motor B through the medium of a suitable operating mechanismC. This motor is supplied with operating current from a suitable source such as a single-phase generator G, the ap plication of current from this generator to the motor beingdirectly controlled by two relays Nand N", which are in turn controlled by a manually operated controlling lever D,

usually one of a plurality of similar levers in an interlocking machine i. The movements of thls lever D arecontrolled by an indication device H, which device is con trolled by current generated at' times by,

motor 13, as hereinafter explained.

K is a circuit breaker arranged to permit the operation of the .motor B by current HOLLIDAY, a

as here shown-is a'jrepulsion Serial No. 4,483.

hereinafter, comprising two field windings F and F, and two pairs of brushes P, P and P, P. The brushes P, P are permanently short circuited by a conductor 10, and the other pair are short-circuited at times as hereinafter explained. The two windings F and F are located substantially 90 electrical degrees apart and the two pairs of brushes are also located substantially 90 electrical degrees apart, the pair P, P being located at an angle to the resultant magnetic field produced by the two windings F and F. Winding Fof switch motor B comprises three sections, 7, f and f When the motor is operatingfas a repulsion motor, section 7' only is energized, this section, cooperatingwith windingF, being sufficient to produce the necessary torque; when, however, the motor is operatingas a single phase induction motor on winding F only, section f and one or the other of the remaining sections of this winding are energized. This arrangement of winding F is desirable because it permits the use of a small motor inan economical manner.

The rotating member of motor B is operatively connected with a screw 11 through the medium of a shaft 103, bevel gears 104., 1045*, and a clutch device M, which latter, as here shown, is mechanically controlled, and may be of a type such as is shown in United States Letters Patent No. 870,912 granted to John D. Taylor on November 12, 1907. .The screw 11 coacts with a threaded block 12 fixed toabar 13, so that this bar may be reciprocated by reverse operations of the motor when the clutch M is operative. The clutch device M is controlled by means of a link 17 having two fingers 17 and 17", one or the other of which is engaged by the block 12 when the bar 13 has reached one extre nity of' its stroke or the other, therebygdisconnecting clutch M. Secured to the bar 13 isa cam platelhaving a cam slot 151 which operates a stud or roller 18, and this stud or roller actuates a rod 16 which is connected with the movable rails of switch A. It will beseemtherefore, that reciprocation of bar 13 will causereverse movementspf switch A. hebes .1 s p r dn th a ,es 9. an which operate two pivotally mounted rocking arms 21 and 22; the arm 21 actuates contacts R, R and R and the arm 22 actuates contacts S, S and S It is understood that the operating mechanism O, which I have just described, is merely illustrative and that any suitable form of mechanism may be employed in lieu thereof.

The supply of current to switch motor B V is controlled bytworelays N and N which are in turn controlled by the manually oper able circuit controller D, as pointed out hereinbefore. Lever D as here shown comprises a longitudinally movable bar 47 which carries two contact blocks 48 and 48 which cooperate with contacts 43, 4:0 andt5. Usually this lever will be one of a number of similar levers comprised in an interlocking machine, and it is understood that this lever may operate suitable means for locking and unlocking other levers of the same machine; such means are well understood in the art and have no bearing on the present invention, hence all illustration and description thereof are omitted.

The indication device H, which controls the movements of lever D, comprises an induction motor 50 having two stator windings 51 and 52 and a rotor 53. The rotor 58 operates a pinion 53 which meshes with a curved rack 54: carried by an arm 55 pivoted at 55 When motor 50 is energized, the arm 55 raises a latch 56 out of the path of dogs 57 and 57. carried by lever 17, thereby permitting the stroke of the lever to be completed. Winding 52 of motor 50 may be short circuited by a low resistance shunt, which shunt isopened and closed by a contact device comprising a block 58 operated by a bar 47 and co'fiperating with two fixed contacts 58 and 58", which contact device operates in such manner that the shunt is closed when-the bar 47 occupies either extreme position of its stroke, and open at all other times. The purpose of this shunt will appear hereinafter.

It is understood that the form of manually operated lever and the form of indication device which I have shown and described are merely illustrative. Several different forms of these devices are known in the art, any of which may be employed in lieu of those which I have shown.

Extending from the control lever D to the circuit relays N and N and switch motor B are three wires 76, 95 and 72; the circuit for an operation of the switch A in one direction includes wires 76 and 72, and the circuit for an operation of theswitch in the other direction includes wires 95 and 72. Hence, I will hereinafter term wires 76 and 95 the control wires and wire 72 the common return wire. I p

The circuitbreaker K comprises two contacts 59 and 59 and a bridging member 59.

The member 59 is biased to the open position by a spring 60 but is held closed against the action of the spring by amotor 61 when the motor is Pro er ne T m torr of the induction type-comprising two stator windings 62 and 63 and a rotor 65. ,The rotor carries a pinion 65 which meshes with rack teeth out in abar66, whichbar is operatively connected with the bridging member 59. The two stator windings are connected at a point 100 and this junction point is connected with one terminal 102 of generator G through a wire 71. The remaining ends of the two motor windings are joined by an impedance 64 which as here shown is a reactance.

and winding 62is connected with a power bus-bar and thence to the other terminal 101 of the generator G through wire 69, contacts 59 and wire. 68, while point 7 3 is connected with'an indication bus-bar and thence, as will later'be shown, with one or the other of the control. wires. ,With this arrangement of the windings, if I current from terminal 101 reaches the motor 61 at point 70 the reactance 64 will be in series with winding 63 and the motor will have torque in such direction as to tend to hold the contacts 59 closed; but in caseof a cross between wires, as pointed out-hereinafter in explaining how the apparatus is protected against false operation by crosses, current from terminal 101 might. reach the motor 61 at point 73, that is, between winding 63 and reactance 64, and in such cases the reactance point 70, thence through windings 62 and 63 in multiple, reactance 64 being in series with winding 63, then through wires 71 and 72 to generator G. The two windings, 62 and 63 are thus supplied with currents of the proper phase relation to energize the motor to hold the contacts 59 closed against the action of spring 60.

I have in the drawing shown a power bus-bar and an indication bus-bar. These two bus-bars extend through a portion of the interlocking machine, and they may serve for a plurality of levers like lever D. In the case of a small. machine having comparatively few levers these two bus-bars may serve for the entire machine. f Only one circuit breaker K is required for each pair of bus-bars. Only one generator G is regeneratormay, if desired, be emplo edror for an entire interlocking machine.

The operation ofthe apparatus is as follows: In the drawing I have shown the switch A in the normal V position, and the corresponding to this position of the switch. When it is desired to move the switch to the reverse position, the manual lever D is moved in the direction indicated by the arrow until stopped by the engagement of,

dog 57 with latch 56. This movement causes contact block 48'? to engage with fiXed contact 40 and contact block 48to engage withfixed contact 13. The winding of relay N is then energized by the following circuit: from terminal v101 of generator. G through wire 68, contact 59 595,9, Wire 69, power bus bar, wire 7 4c, winding 51, wire contact 4l-348, wires 76 vand 103,, contact R wire 104, entire winding 19 of relay N, wire 105, contact 27 of relay N wires 106 and 72 to terminal102of generator G. This causes relay N to close, thereby energizing windings F and f ofinotor B through a circuit which is the same ,as that just traced as far as and including wire 76, then through wire 107, contact 28, wire, 108, sections f of winding F", wire 109, backpoint of contact 28, wires 110 and 111, contact R,wires 112 and 113, winding F, wires 114:

and 7 2 to generator G. At thistime brushes P, P are connected by the reactance 118, but brushes P are shortcircuited and 'are located at an angle to the resultant magnetic field produced by the two motor windings, so that the motorthen operates as repulsion motor and moves the switch During the early part of the movement rocker arm 22 is reversed by cam 20, but this causes no change in the circuits. 1 When theirnove ment of'the switchis completed clutch'lVI is. disengaged by finger l7 and rocker 21,

is reversed by cam 19, thereby reversing contacts R, R, and R The reversalof from the generator G and thereversal of contact R "opens t he original circuit winding 49 of relay N, A new circuit'is now closed, including a portion of rela winding 49, and sections 7 and f of motor w nding 1?, this circuit being thesame as cluding wire 76, then' through wire 107 front point of contact 28, wire 108, section f of winding F,*wire 109, back point of contact 28*, wires 110 and 115, winding section f, w'ire1 1 6, contact R, wire'117,lbwer section of relay fwinding'49, wire'105,con

119 through wires 120 and 121, contact 29, wire 122, contact R, wires 123, and 124, to wire 125. The switch motor B being now disconnected from the switch by clutch M,

c I c, and being already rotating, operates as a remainderof the apparatus in the positions single-phase induction motor on the curand its generates an alternating current in v winding F, theiphase of which is substantially in quadrature to the electromotive force supplied to winding F. This current isemployed'to energize winding-52 of indication motor 50, ,the circuit being from wind,- ing through wires 113 and 126, contact Rflwire 127, contact 26, wire 128, upper section of relay winding 49, wire, 129, contact S wires 130 and 95, contact dSL-iO, wires 96 and 133, motor winding 52, wire 131, in dication bus-bar, wire 97, point 73, through windings 62 and 63 in, multiple, reactanjce 64:,being connected in series with winding 62, wires 71, 72 and 11 1 to motor winding F. The current from generator G in wind ing 51 and the current from winding F in winding52 of the induction motor 50 co-act to operate this motor in such direction as to raise latch 56 out of the path of dog 57?, so that the movement of leverD can becompleted to the position indicated in dash lines. The combined efi'ect on the circuit breaker motor 61 of the indication current supplied at point 73 and of the power current supplied at point 70 is such as to cause the contacts 59 to remain closed, because the E.

l and 63 then differ in phase in the same direction as the currents which reach these windings from generator G through the point 7 0. will be seen that the indication current passes through the upper portion of fwindingflS)? of relay N; owing, however, I to thereactance of this winding and of mo contact R disconnects motor w nd ng F tor winding 52, the current is insufficientto" cause relay N toclose. WVhen, however, the movement of lever D has been completed,

j motor. winding 52 is shunted by contact 58" 8, and wire 132, so that the current in the 'llldlCiltloIl'cllcult then becomes suflicient I to close relay N This opens the back point the previously traced circuits up to and in of contact 27, thereby deenergizing relay N and motor winding F. The motor then controller K. A movement of the switch A in the opposite direction would be accomplished in a manner similar to that just ex;

plain'e' d'; that is, lever D would be moved back toward the position shown in solid plying'current tolmotorwinfldings F and FY,

f'lines, thereby energizing relay N and sup- I c e new "9 iueitiel h let was ing being reversed so that the motor opcrates in the opposite direction to return the switch to normal position. Upon the completion of this movement winding F would again be disconnected from the generator and the current generated in this winding would be employed to control indication motor 50.

The system is protected against false operation by crossed wires (that is, by falsely connected wires) in the following manner: With the parts in the position shown in the drawing, wire 76 is the next control wire, that is, it is the wire to which terminal 101 of generator G will be connected to cause switch A to be reversed, the current returning to the other terminal of generator G through the common return wire 72. This wire 76 might by accident receive current from terminal 101; this might occur, for example, by a cross between wires 7 6 and 95, in which case current would flow from terminal 101 through wire 68, contact 59, wire 69, power bus-bar, wire 74, winding 51, contact 48*, wire 95 to the point of false contact with wire 76, then through wire 76, contact 48, wire 96, winding 52, indication bus-bar, wire 97, then from point 73 through motor windings 62 and 63 in multiple, reactance 64: being in series with winding 62. The torque produced on motor 61 by this current will be opposite to that produced by the current supplied from generator G at the point 70, but since this latter current must pass through the impedances 67 and 67 its effect on the motor will be reduced and the effect of the cross current will predominate so that the motor will be operated by the cross current to open contacts 59. This will open the circuits of relay N and N and motor B so that the switch motor B will therefore not be operated. When the cross is removed, contacts 59 can be again closed by hand and the system is again ready for proper operation. It is, of course, essential that the value of impedances 67 and 67 should be greater than the value of the impedance of.

motor winding 52.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims, without departing from the spirit and scope of my invention. 7

Having thus described my invention, what I claim is:

1. In combination, a railway trafiic con trolling device, electrically controlled means for the operation of said device, a source of single phase alternating current, two control wires, means for connecting one terminal of the said source with one or the other of the 'controlwires, a circuit breaker included between the source and the said means, an alternating current motor for the operation of the circuit breaker which motor comprises two field windings and an impedance the windings being connected with the source in multiple with each other and normally having the impedance in series with one of the windings, whereby the motor has torque in one direction to hold the circuit breaker closed, a

tap at the point between the impedance and other motor winding thereby producing torque in the direction to open the circuit breaker, and means for making the impedance of the normal circuit for the motor comparatively high.

2. In combination, a railway trailic con trolling device, electrically controlled means for the operation of said device, a source of single phase alternating current, two control wires, means for connecting one terminal of the said source with one or the other of the control wires, a circuit breaker included between the source and the said means, an alternating current motor for the operation of the circuit breaker which motor comprises two windings and a reactance the windings being connected with the source in multiple with each other and having the reactance in which the reactance is normally in series,

a circuit controller for connecting said tap with the next control wire, whereby in case of a cross between the next control wire and the terminal of the source which is connected with one or the other of the control single phase alternating current, two con-] trol wires, means for connecting one terminal of the source with one or the other of the control wires, a circuit breaker included between the source and the said electrically controlled means, an induction motor for a the operation of thBISlIClllt breaker said motor comprising two stator windings and an impedance one end of each winding being electrically joined and the junction point being connected with the terminal of the source which is not connected with the control wires, the impedance being connected In testimony whereof I aflix my signature between the remaining ends of the two wind in presence of two witnesses.

ings, the point between the impedance and one winding being connected with the other JOHN HOLLIDAY' 5 terminal of the said source and the point be- Witnesses:

tween the impedance and the other winding A. L. VENQJLL,

being connected with the next control wire. A. G. NOLTE.

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